SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b4a457d0ddba578cc62d9abcea4919d49db5813ab578f91e548e5aca44ee7e0' 
  AND token = 'VAzQCKdxTqvZZlQosBsPz4dr9TJMBKRiijyTKb7d4GQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}